4 wire key switch on TEA20

I just replaced the key switch with a new universal 4 wire switch, now when I try to start it, it starts to turn over the starter before I turn the key all the way to the right, only way to get it to shut off is to turn the key all the way off, I wired the new switch, just like the old one. Any suggestions? Thanks.

Burnt smell doesn't sound good! If it has a dead short that would account for low voltage across the starter solenoid.

Ask an auto electrician to test the starter motor and maybe give you a repair quote as it may be cheaper to repair? If the windings are OK an overhaul should cost around $80, versus a new starter for $150.

The original Lucas starter is better quality than the Chinese or Indian made copies available after market.

OK. If the leads are getting hot the battery may be OK but you have a short somewhere? The switch or solenoid may also be faulty.

I'm not familiar with that switch so can't tell you if it is correctly wired or not, but it doesn't "look" right? The white wire is power into the switch and red wire is power back to the solenoid. One would think the white power in wire should probably go to the switch central position (if that is the power in position?) - but appears to go to the accessory/on position??? Don't change it as I may be completely incorrect?

Where does the red wire on the switch central position go to?

Can you look closely at the black bakelite back on the switch and see if there are any markings on it? My guess it has three positions - "off", "accessory/on" and "start", or maybe four positions "off", "accessory", "on" and "start"?

If you have a multimeter set to continuity, you could disconnect the switch and check it's internal circuitry?

I Googled "wiring diagram universal ignition switch" and came up with a number of sites but THIS may help?

The reason it is hard to help is that your TEA20 never had that switch from new and did not use a starter solenoid. Originally, the starter was engaged by placing the gear lever - "shifter" - into the "S" position, which activates a mechanical switch in the bell housing, behind the engine. Often a solenoid is fitted because often the mechanical switch appears not to work when all it needs is adjustment - it is held in by four screws and adjusts forwards and backwards.

Is the battery ground/earth still connected to the back of the dash or has it been moved to one of the starter bolts? On these old tractors, the dash is a very poor earth/ground and the lead should be moved?

The Lucas starter on your tractor does not give many problems. You could test run it in a vice, by jumpering leads onto the case (ground) and the terminal on the back end of the starter. There is a dust cover around the back of the starter, lossen the screw, remove and you will see the two spring loaded brushes and commutator. The brushes should have "meat" on them - not worn out - and commutator should be bright and clean. An auto electrician should be able to test it for you, for a few dollars.

Sorry about the vague reply, but I am not familiar with that ignition switch. If the black bakelite has any markings on it, post here and I'll see if I can work it out - or someone else may know. I will check my 1966 Jaguar XKE later today as I suspect it has a similar switch, although it has a separate starter button.

The Messiah of Fergusons, John (UK) may be familiar with that switch, as it was common on British cars of the 1950s and 1960s.

I wonder how a TEA20 got to Knoxville? :D Bob in Oz

'53 TEA20

P.S. That is a 12 volt system with 12 volt battery? What is the tractor serial number? If in doubt, the 6 volt and 12 volt Lucas starters are different (6 volt has a nose cone) and I know the Lucas 12 volt starter has "12V" stamped into the case. This post was edited by Bob (Aust) at 12:40:47 10/09/10 7 times.

I think the starter is bad, I pulled it and had it tested, both, with a battery charger, have done this before, doesn't spin. Also jumpered it to battery and grounded to block, still no spin. Also starter has burnt smell to it. Can these be rebuilt or do I need a new one. Might just order a new one and rewire the whole thing, and use the original safety switch. I bought the tractor from someone who had it 5 years, he didn't take very good care of it, sat outside not covered, only paid 500 for it, if it takes a little more money to get it right that is OK. Thanks

OK, have no volts showing from solenoid side to starter when turning the key to start position, I have also noted that both battery cables seem to be getting hot, more so on the negative cable going to the block, nobody responded if what I have is wired correctly from the pictures I posted, where should I start, all new wiring, cables and solenoid? Also nobody has told me yet how to make sure the starter is good, how can i hook it up to a battery to see if it spins? Any help would be great. Thanks

just got the tractor a week ago, this is the way I got it, just want to make it right, runs great when it starts, just need to get the wiring and starter firgured out, where do I check for voltage to starter?

You can also use the gear shift to start it by running a wire fron the inition terminal on the switch to the terminal on the frame and the other terminal on the frame to the starter Solenoid. This way the gear lever will only operate when the key is turned to ignition. Thus you have the safety of not starting in gear. Good luck , Mike

look at the back of your new switch. there should be markings for your terminals. there should be a terminal marked S. that should be the wire going to the starter relay. there should be one marked I or IGN.that wire should be the one going to your coil. then you should have a terminal marked B or BAT. this wire should be coming from the battery to the switch. the last terminal may be accessory or headlight but you should be able to get it starting correctly now. it seems that you have the starter relay wire hooked to the ignition terminal This post was edited by john[mo] at 18:54:12 10/07/10.

note, this has been modified 12 volt system, it by passes the normal start switch on the bell housing and has a starter solenoid, and a 4 wire key switch, which are, Starter, Accessory, Ignition and battery, it also only has the one wire alternator and amp gauge. I did not wire this, so can someone tell me how to wire this, so I don't ruin anything in the process.

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